Individual high-throughput satellites in geosynchronous earth orbit (GEO) over time offer increasing aggregate end-user data throughput. For example, the EchoStar 19 satellite, launched in 2016, offers a data throughput in excess of 200 gigabits per second (Gbps). One limit to achieving terabit per second (Tbps) forward data throughput (also referred to as “data capacity” or “capacity”) from a single GEO satellite is available forward feeder link bandwidth for delivering data to the satellite. With radio frequency (RF) communications, including various “millimeter wave” bands, such rates are generally impractical and expensive. RF feeder links must comply with regulatory constraints and also not conflict with user RF links (the co-siting problem), which makes the following RF bands undesirable:                27.5-28.35 GHz has geographical limitations due to conflicts with 5G cellular communications technology efforts.        28.6-29.1 GHz is utilized by NGSO (non-geostationary orbit) communication satellites, placing the band at risk from various LEO satellite constellation plans.        License-exempt V-band (50-75 GHz) guarantees 4 GHz of bandwidth, with a likely additional 2 GHz, another 2 GHz hopeful, and another 2 GHz in the distant future.        
Plus, at this time, the W-band (75-110 GHz), although it offers 10 GHz, requires further technical development for this purpose for use in GEO RF feeder links. Additionally, even with a spectral efficiency of 2.5 bps/Hz, 400 GHz of total RF bandwidth is required to reach 1 Tbps data capacity, so combined use of the available bands would require about 19 gateways (GWs), plus many additional gateways for diversity. For GEO satellites with data throughput in only a few hundreds of gigabits per second, ground segment costs (construction, operation, and maintenance) for feeder links are already a significant percentage of overall network system cost. For 1 Tbps or greater data throughput, and the resulting increase in the number of gateways, ground segment costs become even more significant. Also, although it may be possible to fit the needed number of gateways in the United States, a very favorable satellite location would still be needed. Thus, in view of significant technology challenges and regulatory uncertainty, use of RF feeders between the Earth's surface and a GEO satellite to achieve terabit per second or higher data throughput is a difficult, uncertain, and expensive architecture.